Osteochondroma of the Rib: A Potentially Life-Threatening Benign Tumor.

Osteochondroma is the most common benign bone tumor. It can be classified as isolated or multiple. While the majority of osteochondromas are asymptomatic and found incidentally, they can become symptomatic during adolescence or adulthood due to mechanical irritation, nerve compression, spinal cord compression, or vascular injury. In this article, we present a case of a 14-year-old patient who experienced spontaneous hemothorax caused by bleeding from a diaphragmatic laceration incurred by a costal exostosis on the right eighth rib. A preoperative chest CT scan revealed a bony projection from the rib and bloody effusion in the thoracic cavity, highlighting the possibility of bloody pleural effusion due to costal exostosis. It is important to note that costal osteochondromas are a rare cause of thoracic injury and can lead to laceration of the lung, diaphragm, and/or pericardium. Surgical intervention should be considered for symptomatic rib osteochondroma, and we advocate for prophylactic surgical removal of intrathoracic exostosis even in asymptomatic patients, in order to prevent potential complications.

Fibrous hamartoma of infancy: imaging findings.

BACKGROUND: Fibrous hamartoma of infancy is a benign tumor that typically arises within the first 2 years of life in the subcutaneous and lower dermal layers. Diagnosis can be challenging as it is a rare tumor, and the imaging appearance is not well known. OBJECTIVE: To describe the imaging features in 4 cases of fibrous hamartoma of infancy focusing on ultrasound (US) and magnetic resonance (MR) findings. MATERIALS AND METHODS: In this retrospective IRB-approved study, informed consent was waived. We searched patient charts for histopathology-confirmed fibrous hamartoma of infancy diagnosis between November 2013 and November 2022. We found four cases, three boys and one girl, and the mean age was 1.4 years (5 months-3 years). The lesions were located in the axilla, posterior elbow, posterior neck, and lower back. All four patients underwent ultrasound evaluation of the lesion, and two patients also underwent MRI evaluation. The imaging findings were reviewed by consensus by two pediatric radiologists. RESULTS: US imaging revealed subcutaneous lesions with variably defined hyperechoic regions and intervening hypoechoic bands resulting in a linear "serpentine" pattern or a "multiple semicircle" pattern. MR imaging evidenced heterogeneous soft tissue masses, localized in the subcutaneous fat, and showed hyperintense fat interspersed with hypointense septations on both T1- and T2-weighted images. CONCLUSION: Fibrous hamartoma of infancy has a suggestive appearance on US with heterogeneous, echogenic subcutaneous lesions with intervening hypoechoic portions, in parallel or circumferential arrangement that can be seen as a serpentine or semicircular pattern. On MRI, interspersed macroscopic fatty components show high signal intensity on T1- and T2-weighted images and reduced signal on fat-suppressed inversion recovery images, with irregular peripheral enhancement.

Immunoisolation of murine islet allografts in vascularized sites through conformal coating with polyethylene glycol.

Islet encapsulation may allow transplantation without immunosuppression, but thus far islets in large microcapsules transplanted in the peritoneal cavity have failed to reverse diabetes in humans. We showed that islet transplantation in confined well-vascularized sites like the epididymal fat pad (EFP) improved graft outcomes, but only conformal coated (CC) islets can be implanted in these sites in curative doses. Here, we showed that CC using polyethylene glycol (PEG) and alginate (ALG) was not immunoisolating because of its high permselectivity and strong allogeneic T cell responses. We refined the CC composition and explored PEG and islet-like extracellular matrix (Matrigel; MG) islet encapsulation (PEG MG) to improve capsule immunoisolation by decreasing its permselectivity and immunogenicity while allowing physiological islet function. Although the efficiency of diabetes reversal of allogeneic but not syngeneic CC islets was lower than that of naked islets, we showed that CC (PEG MG) islets from fully MHC-mismatched Balb/c mice supported long-term (>100 days) survival after transplantation into diabetic C57BL/6 recipients in the EFP site (750-1000 islet equivalents/mouse) in the absence of immunosuppression. Lack of immune cell penetration and T cell allogeneic priming was observed. These studies support the use of CC (PEG MG) for islet encapsulation and transplantation in clinically relevant sites without chronic immunosuppression.